An innate immunity-regulating virulence determinant is uniquely encoded by the Andes virus nucleocapsid protein.
An innate immunity-regulating virulence determinant is uniquely encoded by the Andes virus nucleocapsid protein.
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DOI：
10.1128/mbio.01088-13
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发表时间：
2014-02-18
期刊：
影响因子：
6.4
通讯作者：
Mackow ER
中科院分区：
文献类型：
--
作者：
Cimica V;Dalrymple NA;Roth E;Nasonov A;Mackow ER
安第斯山脉病毒（ANDV）是已知的唯一在人与人之间传播的汉他病毒，并且显示在患者和叙利亚仓鼠中引起高度致命的汉他病毒肺综合征（HPS）。汉坦病毒在人内皮细胞中复制，并通过限制β干扰素（IFN-β）和IFN刺激基因（ISG）的早期诱导来实现这一点。我们的研究揭示ANDV核衣壳（N）蛋白独特地抑制由细胞质双链RNA（dsRNA）传感器RIG-I和MDA 5指导的IFN信号传导应答。相比之下，来自Sin Nombre、纽约-1和前景希尔汉坦病毒的N蛋白对来自IFN-β、IFN刺激的应答元件（ISRE）或κ B启动子的RIG-1/MDA 5指导的转录应答没有影响。消除表达N蛋白的ANDV质粒内潜在的S节段非结构开放阅读框（ORF）（NS）未能改变ANDV N蛋白对IFN的调节。进一步的分析表明，表达ANDV N蛋白可抑制由MAVS、TBK 1和IκB激酶ε（IKKε）指导的下游IFN途径活化，但不能抑制由活性干扰素调节因子IRF 3 -5D组成型表达指导的转录应答或在α干扰素（IFN-α）或肿瘤坏死因子α（TNF-α）刺激后的转录应答。与IFN途径特异性调节一致，ANDV N蛋白抑制TBK 1介导的IRF 3磷酸化（丝氨酸396磷酸化[pS396]）和TBK 1自身磷酸化（pS172）。总的来说，这些发现表明ANDV N通过干扰TBK 1活化、IRF 3磷酸化上游和NF-κB活化来抑制IFN信号传导应答。此外，我们的研究结果表明，ANDV在其N蛋白中独特地携带编码毒力决定簇的基因，该基因能够限制ISG和IFN-β诱导，并为ANDV的新发病机制和传播提供了理论基础。安第斯山脉病毒（ANDV）与其他汉坦病毒的区别在于其在人与人之间传播并在叙利亚仓鼠中引起致命的汉坦病毒肺综合征（HPS）样疾病的独特能力。然而，区分ANDV与其他致病性汉坦病毒的毒力决定因子尚未确定。在这里，我们发现，ANDV独特地包含在其核衣壳（N）蛋白，有效地抑制先天细胞信号转导通路的毒力决定簇。N蛋白的这种新功能为汉坦病毒调节干扰素（IFN）和IFN刺激基因（ISG）诱导提供了一种新的机制，这可能有助于增强ANDV复制、传播和致病的能力。这些发现将ANDV与其他引起HPS的汉他病毒区分开来，并提供了疫苗开发中需要考虑的病毒减毒的潜在靶点。
Andes virus (ANDV) is the only hantavirus known to spread from person to person and shown to cause highly lethal hantavirus pulmonary syndrome (HPS) in patients and Syrian hamsters. Hantaviruses replicate in human endothelial cells and accomplish this by restricting the early induction of beta interferon (IFN-β)- and IFN-stimulated genes (ISGs). Our studies reveal that the ANDV nucleocapsid (N) protein uniquely inhibits IFN signaling responses directed by cytoplasmic double-stranded RNA (dsRNA) sensors RIG-I and MDA5. In contrast, N proteins from Sin Nombre, New York-1, and Prospect Hill hantaviruses had no effect on RIG-I/MDA5-directed transcriptional responses from IFN-β-, IFN-stimulated response element (ISRE)-, or κB-containing promoters. Ablating a potential S-segment nonstructural open reading frame (ORF) (NSs) within the ANDV plasmid expressing N protein failed to alter IFN regulation by ANDV N protein. Further analysis demonstrated that expressing the ANDV N protein inhibited downstream IFN pathway activation directed by MAVS, TBK1, and IκB kinase ε (IKKε) but failed to inhibit transcriptional responses directed by constitutive expression of active interferon regulatory factor IRF3-5D or after stimulation by alpha interferon (IFN-α) or tumor necrosis factor alpha (TNF-α). Consistent with IFN pathway-specific regulation, the ANDV N protein inhibited TBK1-directed IRF3 phosphorylation (phosphorylation of serine 396 [pS396]) and TBK1 autophosphorylation (pS172). Collectively, these findings indicate that the ANDV N inhibits IFN signaling responses by interfering with TBK1 activation, upstream of IRF3 phosphorylation and NF-κB activation. Moreover, our findings reveal that ANDV uniquely carries a gene encoding a virulence determinant within its N protein that is capable of restricting ISG and IFN-β induction and provide a rationale for the novel pathogenesis and spread of ANDV. Andes virus (ANDV) is distinguished from other hantaviruses by its unique ability to spread from person to person and cause lethal hantavirus pulmonary syndrome (HPS)-like disease in Syrian hamsters. However, virulence determinants that distinguish ANDV from other pathogenic hantaviruses have yet to be defined. Here we reveal that ANDV uniquely contains a virulence determinant within its nucleocapsid (N) protein that potently inhibits innate cellular signaling pathways. This novel function of the N protein provides a new mechanism for hantaviruses to regulate interferon (IFN) and IFN-stimulated gene (ISG) induction that is likely to contribute to the enhanced ability of ANDV to replicate, spread, and cause disease. These findings differentiate ANDV from other HPS-causing hantaviruses and provide a potential target for viral attenuation that needs to be considered in vaccine development.